Affiliation: | 1. Faculty of Medicine and Dentistry, Institute of Clinical Odontology‐Community Dentistry, University of Bergen, , Bergen, Norway;2. Department of Dentistry, ?rebro County Council, , ?rebro, Sweden;3. Dental Commissioning Unit ?sterg?tland County Council, , ?rebro, Sweden;4. Department of Oral Public Health, Malm? University, , Malm?, Sweden |